1. Field of the Invention
The present invention relates to an inhaler for changing a liquid and the like containing an active ingredient used for respiratory disease treatment into liquid droplets, thereby allowing a user to inhale the same.
2. Description of the Related Art
As one of the methods for changing a liquid sample to fine liquid droplets and ejecting the same, an ink jet technique is publicly known. The ink jet system has a feature of showing high controllability even when the liquid amount being changed to liquid droplets and ejected is infinitesimal. Types of fine liquid droplet ejection of this ink jet system include a vibration system using a piezoelectric element and the like, and a thermal ink jet system using a micro-heater element. In the thermal ink jet system, reduction of the size of the micro-heater element is relatively easy, and as compared with the vibration system using the piezoelectric element and the like, the number of ejection ports provided per unit area can be increased. Further, the cost required for its manufacture can be significantly reduced.
Many spray apparatuses are adapted to spray a plurality of substances instead of a single composition. Such spray apparatuses are variously used to spray medicine and an auxiliary substance, a plurality of medicines, and the like, and a wide range of medicines are also used such as compounds for disease treatment, fragrant materials, and coloring materials.
Heretofore, when spraying a plurality of materials, a plurality of materials are mixed to complete the ejection in a single operation. However, this has often caused troubles. Even the materials which are stable individually may change in their states and natures when they coexist with other materials under the same atmosphere. Reasons for such a phenomenon may include interactions between ions or due to an electrical charge, interactions for releasing hydrogen bonding, and actions and the like accompanied by π-conjugation. Further, there are various combinations, and this pot life is sustained over a long period in some combinations and is shorter in other combinations.
When spraying the plurality of materials, a mechanism for mixing the liquids immediately before spraying, which is often found in the conventional spraying method, causes liquid droplets to collide with each other, causing the droplets to become large in size or diameter, and does not produce fine liquid droplets. Further, there remains a problem that the amount thereof is unable to be accurately controlled (see WO2002/05898 and WO2004/007346).
While an example of ejecting a plurality of kinds of medicinal solutions is found in the ink jet system, there is no disclosure made on a specific configuration for the mechanism to prevent the collision of the liquid droplets (see U.S. Pat. No. 6,684,880).
Further, there is an inhaler, in which two medicines not storable in one canister in the inhaler of an aerosol system are stored in respective separate canisters, thereby allowing a plurality of medicines to be inhaled by a user (see WO2004/011069, WO2004/011070, and WO2004/011071).